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Can an unbalanced-to-balanced adaptor damage an amplifier?

I just purchased an amplifier that has a 4.4mm balanced (Pentacon) headphone jack.  My Audeze headphone's cables terminate in unbalanced 1/4-inch and minipin plugs.

I don't want to replace my expensive 5-6m cables, so my best option seems to be to pick up some adaptors.  Audeze, however, tells me that using an adaptor to connect an unbalanced plug to an amplifier's balanced jack can damage the amp.

I'm sure that Audeze knows what it's talking about, but I see that the amp's manufacturer (T+A) sells its own quarter-inch-to-Pentacon adaptors, presumably for amplifiers like the one I just bought.  So I want to confirm.

I know that there are two different ways to wire XLR connectors, so I wonder if that's the real issue.

Any opinions?

cundare2

Showing 1 response by erik_squires

erik_squires
16,560 posts
 

The issue for any amplifier, headphone or speaker, is whether the (-) side is active or grounded.

99% of all amplifiers out there only drive the (+) terminal and leave the (-) attached to the signal ground.  Sometimes those amps can be bridged so that you use the (+) of channel A for the red and the (+) of channel B as the black wire.

In the case of grounded negative terminals, there’s no difference between the two speaker (-) terminals and they can be safely jumpered together. The (+) terminal however cannot be jumpered together. Even small differences in voltage can cause massive current flows.

The problem is when the (-), like the (+) side is driven, and the same problem applies. Even a small (0.5V) voltage difference can cause very large current flows to occur. A simple 4 conductor to 3 conductor adapter likely shorts the two (-) together which would be bad.

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